Combined compressor and power cylinder



June 20, 1939. v w. F. BoLD'r ET Al.l

COMBINED COMPRESSOR AND POWER CYLINDER Filed De. 15, 19374 FIG I.

2 Sheets-Sheet l m 3 [TVE: `x 4 K 5 5% M I4.. mLD 0 MOS 2 E B N WF@ v ,WB. 7 v. .A *l v 7 n 7 :E: E 8 I 7 2 6 a 5 A .I /f/// 3 3. l QQ Q\QQQ QQQQQ Q P/3 5. 2 3 n .1. 7 .5 6 3 2 M.. I :z: 4 .l :z 8 4 0 H 4 4 l m \\U 9 ndmllll |ldl\\\w.\\\\ .IH l m m 7 .7 84 3. m -..0. 1...-... l 6 2 22. 2 2 .r..` Il o Il e 9 .E "5 2/ Il' G 6 M//l .2 6 5 3 m.. 2 .r 3 s June 20, *1939. w. F. BOLDT. Er AL COMBINED COMPRESSOR AND POWER CYLINDER 2 Sheets-Sheet 2 Filed Dec. l5, 1957 FIG INVENTORS W.F`. BOLDT BURNS DICK Br TTO Patented June- 20, 1939 2,162,797 COMBINED COMPRESSOR ND CYLINDER Werner F. Boldt, Overland, Dick, Fei'- f guson, Mo., asignar: to Wagner Electric Corporation, St. Louis, Mo., a corporation of Delas Appuemen neeember 15, 1931. serial Ne. 119,860

Our invention relates to braking Amechanism and more particularly to a power-operated comwhich a portion of cylinder 2 is adaptedtg 1pelssor for hydraulically actuated brakes for vec es.

One of the objects of our invention is to produce an improved combined hydraulic compressor and power cylinder whichls compact and durable in construction, efcient in operation and easily. mounted on a support of a vehicle.,

Another object of our invention isto soconstruct a combined hydraulic compressor and power cylinder that when mounted on la support either the compressor or the power cylinder may be removed independently of the other for re- 7 `pair or replacement purposes without thenecessity of removing the part which is secured to the` support.

Still another object of our invention is to pro. duce a combined hydraulic compressor and power cylinder in which the`axes thereof are in alignment and vertically positioned and in which a non-splash reservoir for the compressor. is so built into the dead space of the power cylinder and Figure 4 is a side view showing the mountingarrangeme'nt and other exterior details.

Referring to thel drawings in detail, the reference character I indicates the central mounting member of the combined compressor and powe er cylinder, 2 the cylinder of the compressor unit, and 3 the cylinder. of the power cylindexeY unit. The member I is formed with an 'lar flange 4 to which is detachably secured the flanged end 5 of, the cylinder 3 by means of suitable bolts 6. The lower end of the central member I is formed with an opening ject, the cylinder being attached to the member by means of a ange 1 and securing bolts l.

One side ofthe central member I is formedwlth an integral attaching portion 9 having a flat surface I and bolt receiving openings II whereby unit I can be secured to any convenient supporting member on the vehicle.

The central-mounting member I, lslso (ci. ca -54.6)

with a liquid containing `reservoir I2 for the hydraulic compressor. This reservoir projects upwardly into the lower end of cylinder 3 of the power cylinder.' The reservoir comprises a plurality of separate compartments .I3 (see Figure 2) formed by radial partitions I4 extending incylinder 2. The top wall of the reservoir is dished or recessed and is provided with a central opening I5 aligned with the lower opening. In order to. provide free communication between the several compartments I3 of the reservoir, the lower inner edge of each partition I 4 is out away as indicated at I6 (Figure 1). The top dished wall of the reservoir is also provided with a plurality of holes I1 for permitting free passage of air to and from the top part of theseveral compartments of the reservoir.

The compressor cylinder 2 has reciprocable therein a piston I8, the forward end of which is provided with a'suitable packing cup I9 to prevent leakage past lthe piston during its forward stroke. The piston is normally held in its retracted position against the stop by means of a coil spring 2| interposed between the head end of the piston and the forward end of. cylin der 2. The forward end is adapted to be connected by means of a suitable conduit- 22 to the braking assemblies (not shown) to actuate the brakes thereof when fluid is forced out of cylinder 2 by movement ofthe piston. 'Ihe `wall of the portion of the cylinder within the reservoir, at a point Just forward of thepacking cup I9 when the piston is in its `retracted position, is provided with several compensating ports 23 (Figure 3) in order that any expansion and` contraction of the liquid in the system may be compensated for. These ports also permit anyv excessive fluid in the system to return to the. reservoir after the piston has assumed its retracted position.

The -head of the piston is formed with a plurality of '.arinularly spaced passages 24 which extend from the head surface of the piston to the chamber 25 at the rear of the piston .formed by the piston skirt. This chamber is 4adapted wardly to a point adjacent the upper end of to be in constant communication with the viiuid 'ton, especially inthe chamber thereof.

- engaging the 'endof the cylinder.

passage willbe in communication vwith groove 21 in the forward position of the piston.

The'constructionjust described insures that fluid at al1 times will be at the rear of the pis- Thus, if during the retractile stroke of the piston following a protractile stroke there should be a tendency to create a subatmospheric pressure in the system, liquid will be free to ow from the rear side of the piston through passage y2B and past the lip of packing cup I9 to overcharge the' system.

'I'he cylinder 3 has reclprocably mounted therein a piston 30 provided with suitablepacking rings 3i. The piston is formed with pressed metal and is of dished formationl to lend strength tothe piston. The upper wall of cylinder 3 is also dished as shown in Figure 1 in order that the space between the piston and the end of the cyl-v lnder will be a minimum when the piston is in its fully retracted position. The outer edge of the piston also carries a bumper ring 32 for The top wall of the cylinder has mounted thereon a suitable fitting 33 whereby a conduit 34 may be connected thereto so that air under pressure may be admitted to the cylinder from some suitable source,

' dished top of the reservoir and abuts piston I8 of the compressor.

as for example, a storage tank.

The piston mi has secured thereto a piston rod 35 which extends through the opening I5 in the The lower end of this piston rod is semi-spherically shaped Aand is adapted to cooperate with a semi-spherical recess in the rear side ofthe piston head. A'retractile spring -36 surrounds the piston rod 35 and at its lower end engages the bottom of a cup-shaped member 31 extending through opening I in the dished top of the reservoir and to a point adjacent the head of piston I8- when it is in its retracted position. The upper end of this cup-shaped member 31 is formed with an annular flange 38 which covers the dished portion of the reservoirtop to'form a chamber which is in communication with the compartments I3 by means of openings I1. The lower end oi' the Acup-shaped member 31 also Acarries a guiding andpacking member 41 for the piston rod.

Since the .volume oi cylinder 3 below piston 33 will vary as a result of movement of the piston,

provision is also made to permit air to be expelled and drawn into this portion of the cylinder.

The central mounting member i has formed therein openings 39 (Figure 2) which enter a chamber 40 formed in the mounting portion 9.

Thischamber is lled with a suitable air cleaning material and is open on its lower side tothe atmosphere by means of a plurality of openings 4I (dashed llnesinFlgure 2).

Provision is also made for a breather opening for the several compartments of the reservoir. Referring to Figure 3, this is accomplished by means of a tubular member l2 extending from the exterior through one of the compartments I3 4beyond the attaching ilanges 4 and 5.- A closure plug 46 is provided to close and seal the end of the spout. o

Referring to the operation of the above `described combined compressor and power cylinder,

Vreservoir I2, cylinder 2, and the braking system connected thereto are all 'ilrst filled with a suit- When it is desired to apply the able liquid. brakes, the air under pressure is admitted to the power cylinder through conduit 34 by means of a suitable4 control valve not shown. vThis will cause piston 3I|to move downwardly, forcing ahead of it piston I8 of the compressor. As soon as -the lip of cup I9 passes the compensating ports 23, the liquid in the braking system will be placed under pressure and the brakes applied. When it is desired to release the brakes. the air is exhausted from the power cylinder and spring 36 returns piston 30 to its normally retracted position as shown in Figure 1. Simultaneously spring 2l for the compressor piston I8 causes this piston to return to its retracted position. If the return of piston I8 is more rapid than the return of liquid from the braking system into cylinder 2, there will be created in this cylinder a subatmospheric pressure which will cause liquid to pass from chamber 25 at the rear of piston I8 to cylinder 2 by way oi' passage 24 and then past the lip of the packing cup I9. When piston I8 returns to its retracted position,. this excess of liquid in cylinder 2 will be free to return to the reservoir through the compensating port 23. Since pis- -ton rod 35 only abuts piston I8, piston 30 of the power cylinder is always free to return independently of the compressor piston I3. Also by not having piston rod 36 secured to piston it, any tendency o! piston 30 to become slightly tilted by operation will not produce any unreasonable side binding of piston I8 in cylinder 2.

The' particular construction oi the combined power cylinder and compressor is such that the power cylinder may be removed from the central 'mounting `member I-without the necessity of also removing the member from the support. Thus, if it is necessary to repair or replace any part `of the power cylinder, such can be done without The openings i6 at all times permit the several compartments to freely communicate with each other. The small holes l1r also assist in damping the vvsurging of the liquid for when excess liquid is forced into one of the compartments, it must in turn force air out of this compartment into the other compartments through these passages. The positioning of the reservoir between piston 30 of the power cylinder and the upper end of the compressor cylinder utilizes the dead space in the powercylinder and-thus results in a compact construction with a minimum overall length. The breathertube .42 also insures that clean air can dow into the top of the compartments of the reservoir at all times, thus keeping the liquid free from anyharmful foreign matter. 'I'he air which enters the power cylinder as a result of its movement is also thoroughly cleaned by the cleaning material ll.

Being aware of the possibility of modications in the particular structure herein described without departing from the fundamental princiopenings in its ends, a cylinder detachably secured to one end of the member and having a portion of its length projecting into said reservoir through 'one of said openings, a piston in said cylinder, said piston when in retracted position being positioned in the 'projecting portion of the cylinder, a second cylinder secured to the other end of said member, a piston in said secondcylinder, a'piston rod secured to said second named piston and projecting through the other op'enf ing of said reservoir and'operatively engaging the rst named piston, a sleeve carried by the member and having a piston rod guide portion positioned within the portion of the ilrst named cylinder whichA projects into the reservoir and adjacent the retracted positionl of the piston therein, and a coil spring surrounding the piston rod and interposed between the second piston and the guide portion of the sleeve.

2. In apparatus of the class described, a mounting member providedwith a reservoir, partitions in said reservoir for driving it into a plurality oiv chambers, means for placing the chambers in communication with each other, a cylinder def tachably secured to one end of the member, a

piston mounted in said cylinder, means placing the reservoir chambers in communication with the cylinder when the piston is in retracted p osition, a second cylinder axially aligned with the first cylinder 'and detachably connected with the other end of the member, a piston in the second cylinder, and a piston rod extending through the top ofthe reservoir and operatively connecting the two pistons 3. In apparatus of the class described, 'a mem ber provided with a reservoir, a cylinder detachably secured to one end oi' the member and having a portionof its length projecting into said reservoir, said reservoir having a 'plurality of radially positioned partitions forming with the portion of cylinder therein a plurality of iluid containing chambers, means tor interconnecting the chambers, a piston in the cylinder, means for placing the cylinder vin communication with the chambers when the piston is in retracted position, a second cylinder detachably secured to the other end of said member and receiving cylinder, and a piston rod connecting the two pistons whereby when said second piston is subjected to diiierential iiuid pressure the iirst named piston will be actuated.

4. In apparatus ot the class described, a mounting member provided with a liquid containing reservoir having an opening in its top,' said reservoir having partitions for dividing it into a plurality of compartmets, a cylinder detachably secured to the 'lower end o! the mounting member.

l a piston mounted in saidcylinder, means placing the compartments in communication with each other, means placing the compartments in communication with the cylinder when the piston is in retracted position, a second cylinder detachably secured to the other end of the mounting:l

member, a piston in said'cylinder, a piston rod extending through the top of the reservoir and voperatively connecting the two pistons, means forming a chamber above the vreservoir compartments, and means. for placing said chamber in communicationwith all the compartments.l

' 5. In apparatus of the class described, a mount- 'ing member provided with a reservoir having an annular flange surrounding the intermediate portion oi the reservoir, said reservoir having an opening in its bottom and a recessed top provided with an opening axially aligned with the bottom opening, a cylinder detachably secured to Ythe* lower end of the member and having a portion projecting into the reservoirthrough the bottom opening in the member, means comprising radial partitions in the reservoir and the portion of the cylinder therein forming a plurality of liquid containing compartmentaa piston in the cylinder, means placing the cylinder in communication with all the liquid containingcompartments in the reservoir when the piston is in retracted position, a second cylinder detachably secured to the annular iiange of the member, a piston in said second cylinder, a piston rod operatively con; necting the last named piston with the first named piston and extending through the top opening of the member, a cup-shaped member extending through the top opening of the reservoir in surrounding relation with the piston rod and having a ange covering the recessed top of the reservoir to form a chamber, a coil spring surrounding the -piston rod and interposed between the second named piston and said cupshaped member, and means for placing said chamber in communication with all the fluid containing compartments oi the reservoir.

6. In-apparatus of the class described, a substantially vertically positioned cylinder, a piston reciprocablel therein, a member forming a liquid containing reservoir in surrounding relation with being provided witha plurality of compartments, means for placing the compartments in communication with the cylinder when the piston is in its retracted position, means forming a chamber above the several vcompartments and conimunicating with each oi said compartments by a restricted passage, and means for reciprocating the piston.

7.- In apparatus oi the class described, a chaml a` portion of the reservoir, a piston in the second f hemd' member provided with an openmg-in its rality of radiallypositioned partitions extending the upper portion o! the. cylinder, said member from the cylinder wan therein to the wan or the member and forming a plurality of liquid containing compartments, means for placing thecompartments inV communication with the cylin-v der when the piston is in retracted position, and 4als 

